I am all for people's right to protest, peacefully and would defend their right to speak freely, but..

"Other demonstrators tried to stop the arrest and at least one police officer used CS spray, which hospitalised three people."

If folks are trying to resist/stop arrests..then they are asking for trouble.
I for one, want to see the Police maintaining order, within the law. As a taxpayer, I don't want to be paying the bills for the damage / havoc some protesting marches will create, if the Police are not able to maintain a basic level of control.